chore: honor restic retention settings

Author: Ivan Golman

src/restic_compose_backup/config.py

@@ -30,10 +30,10 @@ def __init__(self, check=True):
         self.log_level = os.environ.get('LOG_LEVEL')
 
         # forget / keep
-        self.keep_daily = os.environ.get('KEEP_DAILY') or "7"
-        self.keep_weekly = os.environ.get('KEEP_WEEKLY') or "4"
-        self.keep_monthly = os.environ.get('KEEP_MONTHLY') or "12"
-        self.keep_yearly = os.environ.get('KEEP_YEARLY') or "3"
+        self.keep_daily = os.environ.get('RESTIC_KEEP_DAILY') or os.environ.get("KEEP_DAILY") or "7"
+        self.keep_weekly = os.environ.get('RESTIC_KEEP_WEEKLY') or os.environ.get("KEEP_WEEKLY") or "4"
+        self.keep_monthly = os.environ.get('RESTIC_KEEP_MONTHLY') or os.environ.get("KEEP_MONTHLY") or "12"
+        self.keep_yearly = os.environ.get('RESTIC_KEEP_YEARLY') or os.environ.get("KEEP_YEARLY") or "3"
 
         if check:
             self.check()